A class of compounds having a polycyclic structure is the class of cyclic-spirodilactones represented by 3,4-(3,5-dimethoxybenzo)--8,9-benzo-1,6-dioxaspiro[4,4]nonane-2,7-dione. This spirodilactone is known, being prepared, for example, by Gourmelon et al., Bull. Soc. Chem., 4032 (1971). It is generally considered characteristic of the spirodilactone ring system that reaction with active hydrogen compounds tends to produce ring-opened derivatives, as exemplified by the above Pariza et al., Synthetic Communications, Vol. 13 (3). pp. 243-254 (1983). publication and by Cowsar, U.S. Pat. No. 4,064,086. It would be of advantage to provide a process for converting the cyclic-spirodilactone ring system into novel functional derivatives while maintaining the spiro ring system.